Sound image on multilayer film



y 1939. 1.. D. MANNES ET AL 2,159,280

SOUND IMAGE 0N MULTILAYER FILM Filed Sept. 18, 1957 1111111111 AFTER M-Q HE, U, M 12 ggfi mw I517 DEVELOPMENT 13 s/LvER g I A 2 AFTER BLEACH/N6 AND 2 1 FIRST coLoR DEVELOPMENT J8 frizk hutaawxtmea 13 26 SILVER HAL/DE 12 s-. JuJfi-Itnfi'iifi 1": HE 5' 25 JARMMHEEMMEEL AFTER COMPLETE COLOR a a l] DEVELOPMENT AND BLEACH/N6 22 T0 SILVER HAL/DE 29 13 slLvE gygaE 12 31 L AFTER PRINTING AND HE A i'lqlmmffimmm 3 DEVELOPMENT OF A 27 SOUND TRACK Leopold D. Mannes Leopold GodawshyJl INVENTOBS W BY AMER M ATTORNEYS Patented May 23, 1939 UNITED STATES PATENT OFFICE SOUND IMAGE ON MULTILAYER FILM Application September 18, 1937, Serial No. 164,543 In Great Britain December 31, 1936 3 Claims.

This invention relates to photographic color films having sound tracks thereon and particularly to a method for producing sound records on such films.

In the production of motion picture films comprising two or more super-imposed layers containing color images, it frequently happens that the colors most suitable for visual reproduction are not those which are most satisfactory for sound reproduction. The sound image should be dark in color, preferably black or at least predominantly minus red or minus infra-red. The sensitive cell used in reproducing the sound is usually red sensitive, and the sound track should absorb red or infra-red light. Furthermore, since the scattering of the light from its passage through one or more emulsion layers impairs its recording power and accordingly impairs the recording of high frequencies, it is important that the image in the sound track shall be in the upper layer or layers.

In multi-layer films for color photography using the subtractive process the outer layer or layer nearest the exposing light rays is usually blue-sensitive and is processed to minus blue, or yellow. This color is unsuitable for the sound track image since it transmits red light and the sound image must, therefore, be made in some other color, or a combination of this color with other colors to produce minus-red or black.

It is, accordingly, an object of the present invention to provide a method for the production of sound images in multilayer photographic films, these images being confined principally to the upper layer or layers and composed preferably of silver or silver and a minus red dye. A further object is to provide a method for the production of a sound track image without affecting the dye image of the picture area. A still further object of the present invention is to provide a method for producing a sound track image without resorting to mechanical means, such as applicator rollers, or physical means, such as protective varnish which permit differential treatment of the sound track and picture areas. Other objects will appear from the following description of our invention.

These objects are accomplished by certain exposure and processing methods which will be described.

In the accompanying drawing Figs. 1 to 4 represent sectional views of a three-layer film having a sound track therein, the various figures representing various stages in the processing treatment.

Our invention relates particularly to the production of a silver or silver and minus red dye sound image in a multi-layer photographic film in which the color images in the layers are produced by color-forming development and after removal of the silver consist of substantially pure dye images. In the production of such films the metallic silver is removed in the final step and, therefore, for the production of a silver or silver and minus red dye image in the sound track the operations of color processing must be carried out in such a manner as to preserve the silver in the sound track area or at least in the upper layer or two upper layers thereof.

A process of this general type is described in our prior Patent No. 2,113,329, granted April 5, 1938. As described in our prior patent the process of forming colored images in a multilayer film consists in exposing the film to a colored object, developing all of the layers in an ordinary developer to silver images, removing the silver and exposing the remaining silver halide to light to form reversed latent images, and developing these images by successive steps to color images of a different color in each of the layers. This operation leaves silver and dye images in the layers. The silver is then bleached to silver halide and removed with hypo to leave clear transparent dye images. In this operation there is no necessity for excluding light after the original bleaching of the silver and color development.

The present process differs from our prior process in two particulars. In order to exclude the sound image from the lower layer or layers of the film, the sound track portion is exposed to red or yellow light at some stage prior to the first development. This completely exposes the loyer red-sensitive layer, or the lower red-sensitive layer and the intermediate green-sensitive layer as the case may be, and this layer or these layers thus exposed are developed and on reversal are entirely clearedof silver. The seconddifference of the present process over that described in our prior application is that the final conversion of the metallic silver in the film to silver halide must be carried out in non-actinic light in order to prevent exposure of any of the portions of the film except those intended to be exposed at that stage. The sound track is printed on the film at this stage of the processing.

In the case of the production of negative and positive films by our color development process, a simpler method is involved. Since it is customary not to print sound tracks on the negative-film but only on the positive film, the sound track may be printed on the positive by exposing the upper layer or layers to blue light or blue-green light.

Our process will now be described with particular reference to the accompanying drawing. As shown in Fig. 1 thereof is the usual transparent support of cellulose nitrate, cellulose acetate, synthetic resin or other suitable material having thereon the layers II, l2 and I3 sensitive, respectively, to red, green and blue light. Either before or after exposure of the picture area A of the film the sound track area B is exposed to red light. It is to be understood that the exposure of the picture area must be limited to the region A and the exposure of the sound area must be limited to the region B in the well known manner. After development in an ordinary MQ developer, the layers ll, l2 and I3 contain the metallic silver images l4, l and I6, respectively, and the layer ll contains in addition the completely exposed and developed silver represented at ll. The developer used at this stage may have the following composition:

Monomethyl p-aminophenol sulfate grams 5 Hydroquinone do Sodium sulfite do '75 Sodium carbonate do 30 Potassium thiocyanate do 1%, Potassium bromide do 2 /2 Formalin (4 cubic centimeters 2 Water to do 1000 The film is then washed and bleached in a bath which removes the silver but does not attack the silver halide present in each layer. This bleach bath may have the following composition:

Cubic centimeters Potassium permanganate (4% solution) 10 Sulfuric acid (20% solution) 10 Water 200 After bleaching the film is again washed and then subjected to a clearing bath of sodium or potassium bisulfite or any other bath capable of removing from the film the manganese compounds or other products that may have been formed in the bleaching operation. A 2% solution of sodium bisulfite is satisfactory. The film is again washed, completely exposed and developed in the first color-forming developer which forms a blue-green dye in each of the layers. A suitable developer has the following composition:

( p-Amino diethyl aniline monohydrochloride grams 3 Sodium sulfite do 5 Sodium carbonate do 50 Potassium thiocyanate do V Water to cubic centimeters" 1000 (b) m-I-Iydroxy or o-hydroxy diphenyl grams 2 Methyl alcohol cubic centimeters 100 (In use, b is added to a) The film after this step is illustrated in Fig. 2. It then contains silver and blue-green dye images I8, l9 and 20 in layers ll, l2 and I3, respectively, and silver and blue-green dye images 2! in the sound track area of layers l2 and I3. The sound track of layer H is clear since the silver which it originally contained was entirely removed in the reversal treatment.

The film is then carried through the customary series of color development steps described in our prior Patent 2,113,329, no special precaution being taken to avoid exposure or development of the sound track portions of layers l2 and I3. This processing results in the formation of silver and dye images in the separate layers.

The next treatment of the film consists of a bleaching in a bath which converts the metallic silver in each of the layers to silver halide without affecting the dye images. A bath suitable for this process may have the following composition:

Potassium ferricyanide grams 20 Potassium bromide do 10 Water cubic centimeters 1000 After this step the film appears as shown in Fig. 3 of the drawing. The layers ll, l2 and I3 contain, respectively, silver halide and dye images 22, 23 and 24 and the layers l2 and I3 contain in the sound track portion completely colored areas 25 and 26. The image in layer II is colored blue-green. The images in layer l2 are colored magenta and the images in layer [3 are colored yellow. This step must be carried out in darkness or in non-actinic light so that the sensitive silver halide formed is not exposed at this time.

After the usual subsequent washings the film is passed through an exposing device which exposes only the sound track portion and a sound track image thereby printed in this portion. For this portion an intense spot of white light may be directed upon the sound track portion while the remainder of the film is carefully masked. The film is then subjected to an ordinary silver developer, containing low sulfite, high bromide and no solvent, after which it is washed and dried as usual. By this means the sensitive halide in only the sound track portion has been exposed and will redevelop and the halide in the remaining picture area will fix out, leaving the clear dye images behind.

The film at this final stage is represented in Fig. 4 in which the layers ll, l2 and I3 contain, respectively, the clear dye images 21, 28 and 29, and the layers I2 and I3 contain in addition in the sound track area the sound images of metallic silver and dye 30 and 3|.

In this method of processing it is to be noted that the sound track portions of the layers 12 and [3 in addition to containing the silver images 30 and 3! are also completely colored with magenta and yellow dyes, respectively. Since the usual electric cells used for reproducing sound are sensitive only to red light, the red produced by the combination of the magenta and yellow dyes has the same effect on the electric cell as white light and can be disregarded.

As a modification of our invention the final development of the sound images 30 and 31 may be carried out in a blue-green color-forming developer to form combined silver and blue-green images in the layers l2 and I3. This has the effect of increasing the opacity of the sound image. This developer may be the same as that used for the production of the blue-green dye image in the red-sensitive layer.

The film which has been processed by the methods described above may have the sound image intensified after processing by rehalogenizing it, for example, with a ferricyanide-bromide bleach followed by washing and redevelopment in a minus red color developer. Any other method of intensification not injurious to the dye image may also be used. Intensifiers involving strong acids or very powerful reducing or oxidizing agents should generally be avoided. The silver sound track image produced as described above may also be converted into a silver sulfide image by any of the usual sulfiding methods.

It is to be understood that the specific method of procedure and the formulae included above are by way of example and that our invention is to be taken as limited only by the scope of the appended claims.

What we claim is:

1. The process of forming picture and sound images in a photographic film having a plurality of layers each sensitive to a different spectral range, which comprises exposing the picture area of the film to a subject and completely exposing at least the lowermost of the lower layers of the sound track area, developing the film in a black and white developer and removing the metallic silver thus formed, redeveloping the remaining silver halide in color-forming developers to form differently colored dye and silver images in each layer, converting the silver to silver halide in non-actinic light to prevent fogging of the picture area, printing and developing to metallic silver a sound image in the sound track area of at least the uppermost layer, and removing the residual silver halide from the film.

2. The process of forming picture and sound images in a multi-layer photographic film having a plurality of layers each sensitive to a different spectral range, which comprises exposing the picture area of the film to a subject and completely exposing at least the lowermost of the lower layers of the sound track area, developing metallic silver images in the exposed portions of the film by means of a black and white developer, removing the developed silver images without affecting the unexposed portions of the film, successively color developing images of metallic silver and a different dye in each of the layers, bleaching the metallic silver images thus formed to a sensitive silver salt in non-actinic light, printing a sound image in at least the upper layer of the sound track portion of the film only and developing it to metallic silver, and removing the unexposed sensitive silver salts from the film.

3. The process of forming picture and sound images in a multi-layer photographic film having a plurality of layers each sensitive to a difierent spectral range, which comprises exposing the picture area of the film to a subject and completely exposing at least the lowermost of the lower layers of the sound track area, developing metallic silver images in the exposed portions of the film by means of a black and white developer, removing the developed silver images without affecting the unexposed portions of the film, successively color developing images of metallic silver and a difierent dye in each of the layers, bleaching the metallic silver images thus formed to silver halide in non-actinic light, printing a sound image in at least the upper layer of the sound track portion of the film only and developing it to metallic silver, and removing the unexposed silver halide from the film.

LEOPOLD D. MANNES. LEOPOLD GODOWSKY, JR. 

